This is an application to continue work on computer technology for transaxial tomography devices. Attention is to be given to reducing further the required time, cost, and dose for improved reconstructions, especially either from data obtained from rapidly moving objects (heart) or large amounts of data covering the extent of a large organ (lungs), and to the displaying of the results obtained from such data in a truly effective way. This will be accomplished through 1) improvements to an existing programming system and data base, 2) development of special purpose algorithms for fanbeam and cone-beam geometries, 3) use of optimization techniques, 4) minicomputer implementation of an operator-interactive graphics system, and 5) development of special purpose algorithms for reconstruction from incomplete and/or limited view projection data. Continued cooperation with medical facilities and manufacturers of computerized transaxial tomography equipment will insure immediate medical application of our work. Particular attention is to be paid to the need for such state-of-the-art developments as the dynamic spatial reconstructor, which is being built at the Mayo Clinic for the study of cardiopulmonary disabilities and low dose detection of cancer lesions.